allow ptrace(2) by default for kernel >= 4.8

Signed-off-by: Henry Wang <henwang@amazon.com>
This commit is contained in:
Henry Wang 2022-04-14 22:32:24 +00:00
parent e0abf62710
commit 94faa70df4
3 changed files with 246 additions and 0 deletions

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@ -0,0 +1,92 @@
/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
File copied and customized based on
https://github.com/moby/moby/tree/v20.10.14/profiles/seccomp/kernel_linux.go
*/
package kernelversion
import (
"bytes"
"fmt"
"sync"
"golang.org/x/sys/unix"
)
// KernelVersion holds information about the kernel.
type KernelVersion struct {
Kernel uint64 // Version of the Kernel (i.e., the "4" in "4.1.2-generic")
Major uint64 // Major revision of the Kernel (i.e., the "1" in "4.1.2-generic")
}
// String implements fmt.Stringer for KernelVersion
func (k *KernelVersion) String() string {
if k.Kernel > 0 || k.Major > 0 {
return fmt.Sprintf("%d.%d", k.Kernel, k.Major)
}
return ""
}
var (
currentKernelVersion *KernelVersion
kernelVersionError error
once sync.Once
)
// getKernelVersion gets the current kernel version.
func getKernelVersion() (*KernelVersion, error) {
once.Do(func() {
var uts unix.Utsname
if err := unix.Uname(&uts); err != nil {
return
}
// Remove the \x00 from the release for Atoi to parse correctly
currentKernelVersion, kernelVersionError = parseRelease(string(uts.Release[:bytes.IndexByte(uts.Release[:], 0)]))
})
return currentKernelVersion, kernelVersionError
}
// parseRelease parses a string and creates a KernelVersion based on it.
func parseRelease(release string) (*KernelVersion, error) {
var version = KernelVersion{}
// We're only make sure we get the "kernel" and "major revision". Sometimes we have
// 3.12.25-gentoo, but sometimes we just have 3.12-1-amd64.
_, err := fmt.Sscanf(release, "%d.%d", &version.Kernel, &version.Major)
if err != nil {
return nil, fmt.Errorf("failed to parse kernel version %q: %w", release, err)
}
return &version, nil
}
// GreaterEqualThan checks if the host's kernel version is greater than, or
// equal to the given kernel version v. Only "kernel version" and "major revision"
// can be specified (e.g., "3.12") and will be taken into account, which means
// that 3.12.25-gentoo and 3.12-1-amd64 are considered equal (kernel: 3, major: 12).
func GreaterEqualThan(minVersion KernelVersion) (bool, error) {
kv, err := getKernelVersion()
if err != nil {
return false, err
}
if kv.Kernel > minVersion.Kernel {
return true, nil
}
if kv.Kernel == minVersion.Kernel && kv.Major >= minVersion.Major {
return true, nil
}
return false, nil
}

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@ -0,0 +1,141 @@
/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
File copied and customized based on
https://github.com/moby/moby/tree/v20.10.14/profiles/seccomp/kernel_linux_test.go
*/
package kernelversion
import (
"fmt"
"testing"
)
func TestGetKernelVersion(t *testing.T) {
version, err := getKernelVersion()
if err != nil {
t.Fatal(err)
}
if version == nil {
t.Fatal("version is nil")
}
if version.Kernel == 0 {
t.Fatal("no kernel version")
}
}
// TestParseRelease tests the ParseRelease() function
func TestParseRelease(t *testing.T) {
tests := []struct {
in string
out KernelVersion
expectedErr error
}{
{in: "3.8", out: KernelVersion{Kernel: 3, Major: 8}},
{in: "3.8.0", out: KernelVersion{Kernel: 3, Major: 8}},
{in: "3.8.0-19-generic", out: KernelVersion{Kernel: 3, Major: 8}},
{in: "3.4.54.longterm-1", out: KernelVersion{Kernel: 3, Major: 4}},
{in: "3.10.0-862.2.3.el7.x86_64", out: KernelVersion{Kernel: 3, Major: 10}},
{in: "3.12.8tag", out: KernelVersion{Kernel: 3, Major: 12}},
{in: "3.12-1-amd64", out: KernelVersion{Kernel: 3, Major: 12}},
{in: "3.12foobar", out: KernelVersion{Kernel: 3, Major: 12}},
{in: "99.999.999-19-generic", out: KernelVersion{Kernel: 99, Major: 999}},
{in: "", expectedErr: fmt.Errorf(`failed to parse kernel version "": EOF`)},
{in: "3", expectedErr: fmt.Errorf(`failed to parse kernel version "3": unexpected EOF`)},
{in: "3.", expectedErr: fmt.Errorf(`failed to parse kernel version "3.": EOF`)},
{in: "3a", expectedErr: fmt.Errorf(`failed to parse kernel version "3a": input does not match format`)},
{in: "3.a", expectedErr: fmt.Errorf(`failed to parse kernel version "3.a": expected integer`)},
{in: "a", expectedErr: fmt.Errorf(`failed to parse kernel version "a": expected integer`)},
{in: "a.a", expectedErr: fmt.Errorf(`failed to parse kernel version "a.a": expected integer`)},
{in: "a.a.a-a", expectedErr: fmt.Errorf(`failed to parse kernel version "a.a.a-a": expected integer`)},
{in: "-3", expectedErr: fmt.Errorf(`failed to parse kernel version "-3": expected integer`)},
{in: "-3.", expectedErr: fmt.Errorf(`failed to parse kernel version "-3.": expected integer`)},
{in: "-3.8", expectedErr: fmt.Errorf(`failed to parse kernel version "-3.8": expected integer`)},
{in: "-3.-8", expectedErr: fmt.Errorf(`failed to parse kernel version "-3.-8": expected integer`)},
{in: "3.-8", expectedErr: fmt.Errorf(`failed to parse kernel version "3.-8": expected integer`)},
}
for _, tc := range tests {
tc := tc
t.Run(tc.in, func(t *testing.T) {
version, err := parseRelease(tc.in)
if tc.expectedErr != nil {
if err == nil {
t.Fatal("expected an error")
}
if err.Error() != tc.expectedErr.Error() {
t.Fatalf("expected: %s, got: %s", tc.expectedErr, err)
}
return
}
if err != nil {
t.Fatal("unexpected error:", err)
}
if version == nil {
t.Fatal("version is nil")
}
if version.Kernel != tc.out.Kernel || version.Major != tc.out.Major {
t.Fatalf("expected: %d.%d, got: %d.%d", tc.out.Kernel, tc.out.Major, version.Kernel, version.Major)
}
})
}
}
func TestGreaterEqualThan(t *testing.T) {
// Get the current kernel version, so that we can make test relative to that
v, err := getKernelVersion()
if err != nil {
t.Fatal(err)
}
tests := []struct {
doc string
in KernelVersion
expected bool
}{
{
doc: "same version",
in: KernelVersion{v.Kernel, v.Major},
expected: true,
},
{
doc: "kernel minus one",
in: KernelVersion{v.Kernel - 1, v.Major},
expected: true,
},
{
doc: "kernel plus one",
in: KernelVersion{v.Kernel + 1, v.Major},
expected: false,
},
{
doc: "major plus one",
in: KernelVersion{v.Kernel, v.Major + 1},
expected: false,
},
}
for _, tc := range tests {
tc := tc
t.Run(tc.doc+": "+tc.in.String(), func(t *testing.T) {
ok, err := GreaterEqualThan(tc.in)
if err != nil {
t.Fatal("unexpected error:", err)
}
if ok != tc.expected {
t.Fatalf("expected: %v, got: %v", tc.expected, ok)
}
})
}
}

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@ -24,6 +24,7 @@ import (
"golang.org/x/sys/unix"
"github.com/containerd/containerd/contrib/seccomp/kernelversion"
"github.com/opencontainers/runtime-spec/specs-go"
)
@ -467,6 +468,18 @@ func DefaultProfile(sp *specs.Spec) *specs.LinuxSeccomp {
Syscalls: syscalls,
}
// include by kernel version
if ok, err := kernelversion.GreaterEqualThan(
kernelversion.KernelVersion{Kernel: 4, Major: 8}); err == nil {
if ok {
s.Syscalls = append(s.Syscalls, specs.LinuxSyscall{
Names: []string{"ptrace"},
Action: specs.ActAllow,
Args: []specs.LinuxSeccompArg{},
})
}
}
// include by arch
switch runtime.GOARCH {
case "ppc64le":